A multi-layer piezoelectric element is basically composed of a stacked body in which piezoelectric layers and internal electrode layers are laminated, and an external electrode bonded to a side surface of the stacked body so as to be electrically connected to the internal electrode layers.
A conventional multi-layer piezoelectric elements is provided with an exterior coating made of an organic material such as silicone resin or an inorganic material such as glass for the prevention of occurrence of leakage current in the surface of its stacked body that will result in variations in displacement. A multi-layer piezoelectric element is known that employs, as an inorganic material-made exterior coating (inorganic coating), a ceramic coating (ceramic cover layer) which is excellent in resistance to heat and resistance to moisture in particular (refer to Patent Literature 1).